Relationship of Strain Variation and Feed Restriction to Variation in Blood Pressure and Response to Heat Stress

Abstract

The response to controlled heat stress and its relationship to blood pressure of chickens differing in body weight and subjected to feed restriction were studied. The genetic variation in body weight associated with strain differences was not related to variation in blood pressure. Blood pressure of the large weight strain was significant reduced when body weight was reduced by restriction of feed consumption, while a similar body weight reduction in a slower growing strain did not result in a decreased blood pressure. The resistance to heat stress of the strains selected for growth was significantly less than that of a slow growing randombred control strain. Restriction of feed consumption of the growth selected strains so that body weights were drastically reduced resulted in a significantly increase in resistance to heat stress.